1. Field of the Invention
The present invention relates to a heat loss preventing apparatus for the Stirling module which prevents a part of working gas, which exists in an expansion space in a cylinder of the Stirling module, from flowing directly to a compression space not through a heat exchanger such as a regenerator and a radiator.
2. Description of the Prior Art
Referring to FIG. 1, a conventional Stirling module includes a heat receiving portion 1 for receiving an outside heat thereof, a regenerator 2 for regenerating the heat received from the heat receiving portion 1, a radiator 3 for discharging the heat from the regenerator 2, a cylinder 8 having an expansion space A provided at an inner upper side thereof and a compression space B provided at an inner lower side thereof, a displacer 4 for expanding or compressing the expansion space A and the compression space B, a piston 5 for compressing the compression space B, a driving section 6 provided at a lower portion of the piston 5 for driving the displacer 4 and the piston 5, and a displacer ring 7 provided between an outer surface of the displacer 4 and the inner surface of the cylinder 8.
The conventional Stirling module is operated as follows.
As the displacer 4 moves to a top dead point of the cylinder 8, a working gas of a high temperature in the expansion space A flows to the compression space B through the regenerator 2 and the radiator 3. In this case, as the displacer 4 is provided for a smooth operation between an outer surface of the displacer 4 and the inner surface of the cylinder 8.
However, at this time, a part of the working gas of high temperature directly moves to the compression space B through a gap between the outer surface of the displacer 4 and the inner surface of the cylinder 8 not through the regenerator 2 and the radiator 3 which are a heat exchanger, due to a high pressure of the working gas of the high temperature in the expansion space A.
In the Stirling module, the displacer ring 7 conventionally plays a role to decrease a friction between the outer surface of the displacer 4 and the inner surface of the cylinder 8, so it has not so good properties for preventing a gas flow through the gap between the outer surface of the displacer 4 and the inner surface of the cylinder 8. Since the working gas of high temperature in the expansion space A, mixed with other working gas which has passed through the heat exchanger, flows directly to the compression space B not through the regenerator 2 and the radiator 3, the heat efficiency is decreased in the Stirling module.